Canon XXIII
The readers and singers have no right to wear an orarium, and to read or sing thus [habited].
Ancient Epitome of Canon XXIII.
Cantors and lectors shall not wear the orarium.
Rightly Zonoras here remarks, “for the same reason (that they should not seem to wish to usurp a ministry not their own) it p. 144 is not permitted to these to wear the stole, for readers are for the work of reading, and singers for singing,” so each one should perform his own office.
This canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars I., Dist. xxiii., can. xxviij.